Informed opinion of the Office 12 beta is that it doesn't include facilities for personalizing the toolbars etc., but that doesn't mean they won't be in the final programs.

The colour probably can't be changed in Windows, but doubtless there'll be concessions for the more sophisticated tastes of Mac users—but they don't know yet what colour will be fashionable then; at the moment it's yellow, brown, or black, apparently.